The balloon recorded the sounds at a height of 22 miles. Image Credit: NASA / Paul A. Newman

A NASA balloon experiment has picked up sounds that wouldn't seem out of place in an X-Files episode.

The eerie sounds were recorded using infrasound microphones attached to a helium balloon that was launched to a height of 22 miles above the Earth's surface.

The audio, which consists of a series of hisses and crackles, could have originated from a number of sources with possibilities including wind turbulence, gravity waves or cable vibrations.

Many of the sounds had never been heard or recorded before.

"There haven't been acoustic recordings in the stratosphere for 50 years," said graduate student Daniel Bowman who designed and constructed the equipment. "Surely, if we place instruments up there, we will find things we haven't seen before."

Infrasound is something that travels very long distances with natural phenomena such as lightning storms, earthquakes, avalanches and volcanoes all producing infrasound sound waves.

There have even been talks of sending infrasound recording equipment to other planets such as Mars in an effort to pick up anomalous weather events or geological disturbances.

Bowman's original audio recording of the strange sounds can be heard in the video below.